Influence of Molasses and Caesalpinia spinosa Meal Inoculums on Biogas Production from Cattle Manure
, Willan Garcia Saldaña 1, Manuel Oliva-Cruz 1, Miguel Ángel Barrena Gurbillon 1,2,*, Carla M. Ordinola Ramirez 1, Oscar Andrés Gamarra-Torres 1 and Diana Carina Mori Servan 1
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe work is within the scope of Fermentation. Here some suggestions for improvement of the manuscript.
Specific comments:
1. The abstract and conclusion are too similar to distinguish them.
2. The "50ml" in the abstract should be written as "50mL”, check the full text for similar errors.
3. Pay attention to the use of punctuation, such as after the reference (8) in paragraph 3 of the introduction, and check for the same errors throughout the text.
4. The first letter of the sentence should be capitalized, for example "hey" in the last paragraph of the second page should be written as" Hey", check the full text for the same error.
5. Context formatting is uniform, for example, paragraphs in 2.5.1pH have no Spaces.
6. Formatting error. Paragraphs 2 and 3 on page 11 should go together.
7. Add a separator for the numbers over 1,000. For example "2000mL" on page 11.
8. Eliminate the use of redundant words, e.g. therefore, first, finally, in addition, in this way.
9. The experimental method section should be more complete and detailed.
10. Does this work fill up some knowledge gaps which previous articles cannot address?
11. The conclusion should further emphasize the contribution of the study, pointing out the limitations of the study and possible future research directions.
12. Note that the format of Table 3 is the same as that of other tables.
Author Response
Comment 1: The abstract and conclusion are too similar to distinguish them.
Response 1: Thank you for your comment, was modified as suggested.
Comment 2: The "50ml" in the abstract should be written as "50mL”, check the full text for similar errors.
Response 2: We agree with your comment, it was reviewed and written as indicated.
Comment 3: Pay attention to the use of punctuation, such as after the reference (8) in paragraph 3 of the introduction, and check for the same errors throughout the text.
Response 3: It was reviewed and corrected as suggested.
Comment 4: The first letter of the sentence should be capitalized, for example "hey" in the last paragraph of the second page should be written as" Hey", check the full text for the same error.
Response 4: The first letters of the sentences were revised and corrected.
Comment 5: Context formatting is uniform, for example, paragraphs in 2.5.1pH have no Spaces.
Response 5: The writing format of the entire document was standardized.
Comment 6: Formatting error. Paragraphs 2 and 3 on page 11 should go together.
Response 6: Joined to the indicated paragraphs.
Comment 7: Add a separator for the numbers over 1,000. For example "2000mL" on page 11.
Response 7: The separator was added to all the top numbers.
Comment 8: Eliminate the use of redundant words, e.g. therefore, first, finally, in addition, in this way.
Response 8: Reviewed and eliminated redundant words from the entire document
Comment 9: The experimental method section should be more complete and detailed.
Response 9: A figure was added to explain the methodology and section 2.3 was modified for better understanding.
Comment 10: Does this work fill up some knowledge gaps which previous articles cannot address?
Response 10: The knowledge gap is explained in the last paragraph of the introduction.
Comment 11:The conclusion should further emphasize the contribution of the study, pointing out the limitations of the study and possible future research directions.
Response 11: The suggested in the last lines of the conclusion paragraph is included.
Comment 12: Note that the format of Table 3 is the same as that of other tables.
Response 12: The format of Table 3 has been modified so that it is the same as the other tables in the document.
Thank you very much for your comments and we have worked to improve the manuscript as suggested.
Reviewer 2 Report
Comments and Suggestions for AuthorsTitle: Influence of molasses and Caesalpinia spinosa meal inoculums on biogas production from cattle manure
Manuscript Number: fermentation-3110436
Authors: Wildor Gosgot Angeles, Euler Willan Garcia Saldaña, Segundo Manuel Oliva Cruz, Miguel Ángel Barrena Gurbillon, Carla María Ordinola Ramirez, Oscar Andrés Gamarra Torres, Diana Carina Mori Servan
General comments:
The manuscript titled "Influence of molasses and Caesalpinia spinosa meal inoculums on biogas production from cattle manure" investigates two types of systems for biogas production with different inoculums. The results determined that thermostat-controlled heating system yield high biogas of 619.6 19 mL/day compared with other systems. In terms of (CH4) 76.9% was obtained, which allows the production of biogas with a high concentration of methane. Although the manuscript is well written and within the scope of the journal. But what is the novelty of the work, this approach is adopted decades ago and the same them of work and approach you can find in the literature. Overall, the manuscript is written very well in terms of language but in terms of scientific background (Novelty) its lakes. The authors need to elaborate the novelty statement with solid literature comparison and address the major comments I would recommend to be accepted.
Keywords: “Hydraulic retention time; Renewable Energy” these keywords need to replace with other common words expressed in the manuscript.
Abstract:
1. The sequence and connection of the sentences is well justified and of the spot, the problem presented and tackle very well but the novelty is lacking in the study.
2. Line: 20: “T1” expressed the condition of the treatment, don’t only use the code of the treatment.
Introduction:
1. Line: 43: “One of the substrates” correct it.
2. Line: 55: “Estudies….. means?
3. Lines: 67-68: “tannins, phenolic compounds and other antioxidants” the phenolic compounds and antioxidants are consider as inhibitor of the anaerobic system. Provide some literature about these claims that these can optimize biogas production.
4. Lines: 70-71: “Tannins, in particular, can act as protective agents against microbial inhibition caused by ammonia and volatile fatty acids, thus stabilizing the digestion process”. These lines are not correct if they are protective against microbial inhibition so need some references to validate it.
5. Line: 70: “In this sense” replace it.
Novelty:
The authors are suggested to revise the novelty of the paper, as mentioned in the general comments section.
Materials and Methods:
1. Section: 2.1.1: Caesalpinia spinosa meal: “with a number 12 sieve” please clear it with the pore size.
2. Section: 2.1.1- 2.1.2: none of the substrate’s collection was mentioned means the method and the origin, from where these were collected.
3. Lines: 124-125: “Rainwater was used to mix the manure with the other substrates”. Why the rainwater was used, what’s the logic behind it.
4. What was the Total solids (TS) of the reactors, as one of the main factors for anaerobic digestion process.
5. Table 2: Proportions of substrate for each treatment: can the authors check how the Total working Volume (2800) of the reactors was achieved: as according to my calculations A). T1: 400+300+30+2000=2730 and so on…..
6. 2.5.1 pH: Does the pH was maintained as mentioned in this section than how it was maintained provide the detail.
7. Measurement of biogas: as mentioned by the authors the biogas was measured by water displacement method, so provide the reference of the method.
8. Table 4: Total Solids Values (%): the Total Solids Values mentioned here are too high for the anaerobic digestion, can the authors explain it did it effect the process.
Results and Discussion:
1. Line: 218: “evaluation period” replace it with digestion period. More appropriate.
2. Figure 1: Text Lines: 222 and 223: here the authors mentioned the highest biogas production was 648.4874 mL/day and in the abstract, it was mentioned 619 mL/day. The production was expressed in hours and in 43 days incubation period it’s a bit confusing.
3. The results achieved are interesting but the authors should make it clearer and smoother because for common readers its confusing.
4. In the introduction the authors mentioned the importance of phenolic compounds etc as with ammonia and VFA, but here is no such analysis were done so I would suggest avoid such statement if there is no such analysis done in the current study.
5. In my point of view the authors didn’t explain the results as well the discussion, so add some more discussion by adding recent literature.
Conclusion:
1. I have noticed the prominent points of the current work presented in abstract are different here as here in this section 625.9 mL/day, 736.3 mL/day…. But the story there are totally different.
2. Please cross check there is contradiction in these results presented.
Author Response
Comment: Keywords: “Hydraulic retention time; Renewable Energy” these keywords need to replace with other common words expressed in the manuscript. Response: The above words were replaced by "biodigestion" "heating system"
Abstract:
Comment 1: The sequence and connection of the sentences is well justified and of the spot, the problem presented and tackle very well but the novelty is lacking in the study.
Response 1: Thank you for your comment. I have rewritten and added the newness of the study.
Comment 2: “T1” expressed the condition of the treatment, don’t only use the code of the treatment.
Response 2: The condition of the treatment was expressed as follows.
Introduction:
Comment 1: Line: 43: “One of the substrates” correct it.
Response 1: The aforementioned sentence was corrected.
Comment 2: Line: 55: “Estudies….. means?
Response 2: There was a translation mix-up, Studies was corrected.
Comment 3: Lines: 67-68: “tannins, phenolic compounds and other antioxidants” the phenolic compounds and antioxidants are consider as inhibitor of the anaerobic system. Provide some literature about these claims that these can optimize biogas production.
Response 3: The referential information has been verified and the text has been modified.
Comment 4: Lines: 70-71: “Tannins, in particular, can act as protective agents against microbial inhibition caused by ammonia and volatile fatty acids, thus stabilizing the digestion process”. These lines are not correct if they are protective against microbial inhibition so need some references to validate it.
Response 4: The referential information has been verified and the text has been modified.
Comment 5: Line: 70: “In this sense” replace it.
Response 5: The above-mentioned words were replaced.
Materials and Methods:
Comment 1: Section: 2.1.1: Caesalpinia spinosa meal: “with a number 12 sieve” please clear it with the pore size.
Response 1:
Comment 2: Section: 2.1.1- 2.1.2: none of the substrate’s collection was mentioned means the method and the origin, from where these were collected.
Response 2:
Comment 3: Lines: 124-125: “Rainwater was used to mix the manure with the other substrates”. Why the rainwater was used, what’s the logic behind it.
Response 3:
Comment 4: What was the Total solids (TS) of the reactors, as one of the main factors for anaerobic digestion process.
Response 4:
Comment 5: Table 2: Proportions of substrate for each treatment: can the authors check how the Total working Volume (2800) of the reactors was achieved: as according to my calculations A). T1: 400+300+30+2000=2730 and so on…..
Response 5: Se menciona 2800 mL como referencia a la capacidad máxima de trabajo de todos. Asimismo también hay tener en cuenta que en el caso del estiércol se trabajo en base a gramos y los demás sustratos en mL.
Comment 6: 2.5.1 pH: Does the pH was maintained as mentioned in this section than how it was maintained provide the detail.
Response 6: Yes, the pH was kept constant as mentioned in this section.
Comment 7: Measurement of biogas: as mentioned by the authors the biogas was measured by water displacement method, so provide the reference of the method.
Response 7: The graphical reference of the method is included in Figure 1.
Comment 8: Table 4: Total Solids Values (%): the Total Solids Values mentioned here are too high for the anaerobic digestion, can the authors explain it did it effect the process.
Response 8: Yes, the total solids values mentioned here are higher than usual for anaerobic digestion. However, this was done for the purpose of obtaining a robust and active inoculum.
Results and Discussion:
Comment 1: Line: 218: “evaluation period” replace it with digestion period. More appropriate.
Response 1: "Evaluation period" is replaced as suggested.
Comment 2: Figure 1: Text Lines: 222 and 223: here the authors mentioned the highest biogas production was 648.4874 mL/day and in the abstract, it was mentioned 619 mL/day. The production was expressed in hours and in 43 days incubation period it’s a bit confusing.
Response 2: A new figure (Figure 2) has been added to be more explanatory of what we want to present.
Comment 3: Lines: 124-125: “Rainwater was used to mix the manure with the other substrates”. Why the rainwater was used, what’s the logic behind it.
Response 3: Improved by taking into account your comment.
Comment 4: In the introduction the authors mentioned the importance of phenolic compounds etc as with ammonia and VFA, but here is no such analysis were done so I would suggest avoid such statement if there is no such analysis done in the current study.
Response 4: The above information has been removed.
Comment 5: In my point of view the authors didn’t explain the results as well the discussion, so add some more discussion by adding recent literature.
Response 5: The above information has been removed.
Conclusion:
Comment 1: I have noticed the prominent points of the current work presented in abstract are different here as here in this section 625.9 mL/day, 736.3 mL/day…. But the story there are totally different.
Response 1: Revised and redrafted what is intended to be disclosed.
Comment 2: Please cross check there is contradiction in these results presented.
Response 2: The results were verified as suggested.
Reviewer 3 Report
Comments and Suggestions for AuthorsThe manuscript by Angeles and co-workers explored the production of biogas from different waste substrates. A set of production conditions was tested in a promising low-cost system.
Comments
L 49-50. This part of the text is repetitive, please rewrite it.
L 60. Please clarify 'activity'.
L 71-72. Briefly expand on how Caesalpinia spinosa meal can contribute to the decomposition of lignocellulosic material. Rewrite.
L 80. Is tare meal the same as Caesalpinia spinosa meal? Please mention it when it appears for the first time in the text.
L 83-88. Please add the amount of substrate (molasses, Caesalpinia spinosa meal) available per year (regionally and/or worldwide) that could support biogas production.
L 110. Please consider adding a schematic figure summarizing the methodology (substrates used, measured parameters, etc).
L 144. It is unclear how T1 differs from T4 (same for T2 and T5, T3 and T6). Please review Table 1.
L 219. Yield usually refers to the quantity of product obtained per 1 quantity of substrate (in g/g, mol/mol, etc). Please revise the use of yield throughout the text.
L 222-227. Please revise the use of 7 significant figures in the text and table.
L 304. Please correct 'figure xx'.
L 371-372. If possible, include pictures of the system constructed in this work.
L 383. Please clarify 'metagenomic battery selector'.
L 389. Please present and discuss the process yields and volumetric productivities.
L 403. Standardize to mL/day or m3/day throughout the text.
L 413. Please correct to NH3, N2, and so on.
L 424. It is not clear whether microorganisms were added or whether they were present in the substrates. Please clarify the text.
Comments on the Quality of English LanguageMinor editing of English language required.
Author Response
Comment: L 49-50. This part of the text is repetitive, please rewrite it.
Response: Thank you for your comment, the indicated part has been rewritten.
Comment: L 60. Please clarify 'activity'.
Response: The word "activity" was clarified as it refers to microbial activity.
Comment: L 71-72. Briefly expand on how Caesalpinia spinosa meal can contribute to the decomposition of lignocellulosic material. Rewrite.
Response: The referential information was verified and the text was modified.
Comment: L 80. Is tare meal the same as Caesalpinia spinosa meal? Please mention it when it appears for the first time in the text.
Response: It was written as suggested.
Comment: L 83-88. Please add the amount of substrate (molasses, Caesalpinia spinosa meal) available per year (regionally and/or worldwide) that could support biogas production.
Response: A new paragraph with this information was added after the lines mentioned above.
Comment: L 110. Please consider adding a schematic figure summarizing the methodology (substrates used, measured parameters, etc).
Response: A figure (Figure 1) with a summary of the methodology was added in section 2.3.
Comment: L 144. It is unclear how T1 differs from T4 (same for T2 and T5, T3 and T6). Please review Table 1.
Response: The description of the treatments was rewritten and Table 2 was modified.
Comment: L 219. Yield usually refers to the quantity of product obtained per 1 quantity of substrate (in g/g, mol/mol, etc). Please revise the use of yield throughout the text.
Response: The yield is presented in Volume per substrate mix.
Comment: L 222-227. Please revise the use of 7 significant figures in the text and table.
Response: Improved by taking into account your comment.
Comment: L 304. Please correct 'figure xx'.
Response: The figure number was corrected.
Comment: L 371-372. If possible, include pictures of the system constructed in this work.
Response: Photographs are included in the graphical summary.
Comment: L 383. Please clarify 'metagenomic battery selector'.
Response: I revise and change the term to "methanogenic bacteria".
Comment: L 389. Please present and discuss the process yields and volumetric productivities.
Response:
Comment: L 403. Standardize to mL/day or m3/day throughout the text.
Response: Improved by taking into account your comment
Comment: L 413. Please correct to NH3, N2, and so on.
Response: He corrected himself taking into account his comment.
Comment: L 424. It is not clear whether microorganisms were added or whether they were present in the substrates. Please clarify the text.
Response: It was not added, the manure used contained the microorganisms.
Thank you very much for your comments and we have worked to improve the manuscript as suggested.
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsI have no more suggestions for the manuscript.
Reviewer 2 Report
Comments and Suggestions for AuthorsThe authors addressed the raised questions, but the authors needs to carefully check the references i still beleive there is format and standrd issue.
My recommendation is can be accepted but after references thorough checking.
